The War Illustrated, Volume 1, No. 2, Page 54, September 23, 1939.

Faced by the same menace from the air as that which has preoccupied the minds of Britain’s defence chiefs during the past few years, Germany has developed her own A.R.P. organisation which reproduces many of the defence practices which have been carried out in our own country. Gas masks have been produced on a large scale, and have been distributed to those who can buy them; A.R.P. wardens, decontamination squads, auxiliary firemen and the like have been enlisted and trained; and up above float balloon barrages.

Taken near Berlin this photograph shows three balloons of the German capital's balloon barrage ascending during training.

Photo: The Miriam and Ira D. Wallach Division of Art, Prints and Photographs: Picture Collection, The New York Public Library. "[The barrage balloons of the German Luftwaffe.]" The New York Public Library Digital Collections. 1939.